Infrared (IR) spectroscopy is routinely used for material identification and characterization. Numerous chemical functional groups have characteristic absorption bands and absorption patterns (called “fingerprints”) in the IR spectrum that allow determining, or at least narrowing the possibilities for, the types of molecules present in a sample. A common laboratory instrument used for IR spectroscopy is a Fourier transform infrared (FTIR) spectrometer. FTIR spectrometers are benchtop-size apparatus that generally test one sample at a time; are not easily portable; and, as a result, cannot be easily used in the field. In recent years, therefore, efforts have been made to develop chip-scale photonics-based IR spectrometers and biochemical sensors, which provide cost savings and the potential to integrate many sensors into arrays for high-throughput testing. Standard photonic material platforms, such as silicon (Si) or silicon-nitride (SiNx) on silicon oxide (SiO2) or sapphire, however, are limited in their operational wavelength range. While Si and SiNx are IR-transparent up to about 8 μm, the SiO2 and sapphire undercladdings become opaque at 3.7 and 4.5 μm, which limits or precludes sensing applications at longer IR wavelengths.